\documentclass{article}

\usepackage{graphicx}

\begin{document}

\begin{figure}[ht]
  \centering
  \includegraphics[width=1.0\textwidth]{figure.1}
%  \includegraphics[scale=1]{figure.1}
  \caption{Expression}
\end{figure}

\begin{figure}[ht]
  \centering
%  \includegraphics[width=\textwidth]{figure.1}
  \includegraphics[scale=1]{figure.1}
  \caption{Expression}
\end{figure}


\clearpage
\end{document}
